Friday, February 22, 2008
Wednesday, February 20, 2008
Sunday, February 17, 2008
When I examined the whole DCO control logic, I found something surprising. When the CPU is computing the digital count value to be loaded into the timer, and fed to the D/A converter to produce the control voltage, it takes into account the things you'd expect -- the note that was played, pitch bend, LFO, and portamento. However, it does not take into account the range selection! Interestingly, the 8 MHz master clock, contrary to conventional wisdom, is never seen directly by the DCO timers. Instead, it goes through a divider which divides the master clock down according to the DCO range selection:
- 4' range: 4 MHz
- 8' range: 2 MHz
- 16' range: 1 MHz
Friday, February 15, 2008
A post is coming this weekend on DCOs, but I'm not sure exactly when I'll have it up -- got a lot going on right now.
Saturday, February 9, 2008
Tuesday, February 5, 2008
- The 800 must be in SINGLE mode for this to work; if it is in MULTI mode it will not send the right sysex strings.
- Yes, the Palette sliders work to edit the 990. In fact, you can do the same trick you can do on the 800, where you have no Tones active and then you move a slider, editing nothing but making that parameter the current parameter for the Palette.
- Keep in mind what structure you have selected on the 990 when editing from the 800. The 800 doesn't know about structures; you may think that you are editing only tone A's VCF, but if you have selected a different structure, it may effect both tones A and B, for instance.
- Remember that even an un-expanded 990 has waveforms that the 800 doesn't have. You cannot access all of the waveforms using the 800's waveform selection knob. If you want to select a waveform numbered higher than 128, you'll have to go to the 990's screen. You'll also have to do this if you want to select a waveform from an expansion board.
- The 990's LFOs also have a few extra waveforms that can't be selected from the 800.
- You cannot edit the 990's effects parameters from the 800.